1. Field of the Invention
The present invention relates to a biaxial hinge device suitably applied to cellular telephone devices, PHS (Personal Handyphone System) telephone devices, PDA (Personal Digital Assistant) devices, portable game devices, notebook computers, and so forth, which have a hinge portion enabling opening/closing of a housing, for example, and to a portable terminal device. More particularly, the present invention relates to a biaxial hinge device having two rotational axes and to a portable terminal device wherein the overall size and the like has been reduced by enabling a single spring member to serve in the place of spring members used for each rotational shaft with the related art, thereby reducing the number of spring members.
2. Description of the Related Art
Japanese Unexamined Patent Application Publication No. 2005-198062 (pp. 8-9, FIG. 5) discloses in a clamshell type cellular telephone device having three folding functions which are a function of opening/closing in the longitudinal direction of an upper housing, a function of opening/closing in the lateral direction, and a function of folding in a state of the front and back of the upper housing having been inverted.
This clamshell type cellular telephone device has a hinge unit configured separately of a first hinge unit and a second hinge unit. The first hinge unit has a first rotational shaft rotatably supporting the first hinge unit itself as to a lower housing, and a second rotational shaft rotatably supporting the second hinge unit as to the first hinge unit, with the first rotational shaft and the second rotational shaft disposed in a mutually orthogonal arrangement. The second hinge unit is provided with a third rotational shaft which rotationally supports the upper housing as to the second hinge unit, such that the second rotational shaft is disposed orthogonal to the second rotational shaft. Accordingly, the upper housing can be rotated on each of the rotational shaft directions of the first rotational shaft, second rotational shaft, and third rotational shaft.